In wireless mobility engineering, the term near-far generally refers to a condition in which mobile devices very close to a radio transceiver base station (BS) present noise levels that mask other signals that the radio transceiver BS may need to acquire. One may incorrectly assume that signals from mobile devices on different frequencies are isolated from one another and therefore do not interfere with one another. However, both mobile device and BS radio transmissions can occupy a power mask that specifies filter characteristics of the transmitted signals. These specifications can allow a small portion of transmitted power to leak into adjacent frequencies. When both mobile devices are at roughly the same distance from the radio BS, this leakage is insignificant and may not impair signal receiving. However, as one mobile device moves farther away from the radio BS, the signal strength of the signal from the mobile device can drop. As such, the ratio of the signal power from the mobile device to the power leakage from an adjacent frequency can be reduced. As the mobile device on the adjacent frequency moves closer to the radio BS, the ratio can be further reduced. Eventually, the ratio can be reduced to the extent that the receipt of a signal from a mobile device further from the radio BS can be impaired.
Generally, as mobile devices approach a radio BS, the transmissions of the mobile devices are powered down, thereby reducing the near-far effect. As such, when more than one mobile device is served by the same radio BS, the near-far effect is minimal and not considered a primary driver of call performance. However, when a mobile device that is near a particular radio BS is served by a distance radio BS, the mobile device may not be powered down. This is the condition that can present the “performance-affecting” near-far effect.
This performance-affecting near-far effect can exist when a mobile device using another telecommunication company service is being served by a radio BS that may be miles away, causing the mobile device to transmit at high power right next to a nearby radio BS associated with another telecommunications company service.
This performance-affecting near-far effect can also exist when different mobile radio network access technologies (e.g., Global System for Mobile Communications (GSM), Universal Mobile Telecommunications System (UMTS)) are used in the same network, but are not equipped on all BSs within that network. For example, a mobile device may be using UMTS radio access technology and may move into close proximity of a BS not equipped with UMTS radio access technology. Since the mobile device cannot make a handoff to a UMTS radio on that BS, the mobile device will transmit at a power level much higher than would be the case if the BS was equipped with a UMTS radio. This configuration often occurs during network-wide roll-out of a new radio access technology and there is a temporal factor in all radio BSs being equipped with the new technology. During the intervening period, the sparseness of radio deployments on the new technology are generally referred to as a Swiss cheese network where the holes imply BSs not having the new access technology radios.